Prof Luis Alvarez and the Ground Control Approach Trials at Elsham Wolds - 1943 .
Luis Alvarez (1911 to 1988) is considered to be the greatest experimental physicist of the 20th Century and was awarded the Nobel Prize for Physics in 1968. Pre war Alvarez was one of the American pioneers in the field of nuclear fission.
In 1940 he moved from the University of California to the Massachusetts Institute of Technology where he was responsible for the development of a number of very important radar systems. Amongst these was the revolutionary the Ground ControlApproach ( GCA) system which was also referred to as the Alvarez Talk Down System. The system enabled air-traffic controllers to guide aircraft to a safe landing at night or in adverse weather conditions based on radar images.
The RAF were particularly interested in this project and Alvarez personally came to England with his team to demonstrate the system in the summer of 1943. The first site chosen for the highly secret trials was Elsham Wolds.
Alvarez refers to this visit in his book Alavarez - Adventures of a Physicist and the following is an edited version of his account.
"My GCA group was stationed at Elsham Wolds, an RAF bomber aerodrome, later in the summer. A British Pathfinder pilot delivered me there in a new B-17 Flying Fortress on loan from the US Air Force and being used for evaluation. I rode as co-pilot. The pilot liked the plane very much exploring the knobs and switches and pronounced it a wizard kite. He was mystified by the small bomb bay however and found it hard to believe that an aircraft the size of the B-17 had been designed to a carry such a small volume of bombs. The British bombers carried enormous loads by comparison.
The station commander at Elsham Wolds was happy to allow GCA tests on his base so long as we did not interfere with his bombing missions. During the first week I met my American GCA colleagues at Victoria Station and introduced them to wartime England. We located our GCA set, picked up our RAF drivers to deliver the two trucks and met our WAAF contingent, the women who would be our drivers and baby sitters for the next two months. Our WAAFs were all Corporals - and one was a Lady !
They shuttled us back and forth each day from the Angel Hotel, our comfortable quarters at Brigg, to Elsham Wolds. The hotel proprietress, a very special person, kept her own hens; we quickly became friends. She provided each of us with an unbelievable treat of a fresh egg for breakfast every morning. I remember as the high point of an RAF party the auctioning off of a pair of fresh eggs; the station commander successfully bid £5 and everyone thought he had done very well.
For six weeks I lived in intimate association with men whose daily job it was fighting a war and who too frequently disappeared from the dining room never to be seen again. When the bombers were flying in bad weather we stood by. In good weather we repaired to the local pub and practised tolerating English beer.
The GCA system consisted of two trucks half way down the runway parked 50 ft from the left edge from the pilot's point of view. The larger of the trucks consisted of a gasolene generator behind the driver with an azimuth antenna which looked downwind at approaching aircraft rocking left and right. At the rear was a tall elevation antenna scanning up and down. The area search antenna was mounted above the generator. The second truck was positioned ahead of the antenna truck looking in the direction of the landing aircraft and contained the controller and screens.
Our GCA tests were successful beyond expectation. We landed every type of plane the RAF operated, every rank of pilot from Sergeant to Air Chief Marshal and on several occasions the entire Elsham Wolds bomber Squadron returning from a mission over Germany.
The mission landings were important tests. It is one thing to approach a foggy airport on instruments after a good nights sleep but quite another to do so after eight hours over hostile territory in a damaged aircraft with wounded on board. We brought them in, those who came back.
When Air Chief Marshal Sir Ludlow-Hewitt, then Inspector General of the RAF, visited Elsham Wolds he was impressed by the great variety of planes and pilots we had landed but noticed that we had never bagged a tired fighter pilot. He proceeded to order one up, a Typhoon returning from a long patrol over the North Sea. Squadron Leader Mingard, who I had trained on the system, did the controlling and I had the pleasure of standing outside the GCA truck as the Air Chief Marshall listened in.
The Typhoon pilot was Polish and did not know much English but enough to manage. He appeared out of the overcast at 200 feet directly over the runway centre line made a touch and go and went round again. Mingard asked the Pole what he thought of the system. "Wizard, absolutely wizard" he shouted.
The normal complement at Elsham Wolds was eighteen Lancasters. Mission losses dictated that usually fewer were on hand. The Lanc was a vast black four engined bomber with twin vertical stabilisers and a huge bomb bay.
The standard RAF tour of duty made the odds of survival very small and the crews were understandably fatalistic.
On 24th July I attended a briefing at Elsham Wolds for a raid on Hamburg. It was one of the first raids in which the WINDOW radar jamming technique was used which consisted of strips of aluminium foil dropped from the bombers at regular intervals. We watched the bombers take off, ate dinner and waited. It was fascinating to sit in on the debriefing when the crews returned from their mission. The WINDOW had effectively blinded the German Ground Control Intercept (GCI) radars and the night fighters they controlled. From the total Force dispatched by Bomber Command only twelve bombers were lost but sadly three came from Elsham Wolds. The Squadron Commander was not impressed and referred to WINDOW as an "Abomination".
Standing in the Officer’s club bar one day I was surprised by a powerful explosion that shook the building and rattled the windows. We ran outside to see a thick plume of black smoke rising from where C Charlie was usually parked. A two ton Cookie, one of the unfinned cans of high explosive that the RAF dropped on German targets, had gone off. Two of the Lanc’s large Rolls-Royce engines had been blown several hundred yards away. A third turned up next day half a mile from the aerodrome. The fourth was still missing when I left England at the end of the August".
During his visit to the UK Alvarez was invited to a Bomber Command briefing near Cambridge. He was flown down in a Miles Magister by his RAF colleague Sqdn Leader Mingard. The aircraft sustained an engine failure and force landed heavily. He also visited a station in the Home Radar Chain at Dover to inspect the Early Warning radars then in use and the Cavendish Laboratory where he met his old friend Bernard Kinsey who briefed him on British Atomic Bomb research progress. Alvarez then returned to the USA and joined the American A Bomb development team at Los Alamos.
Here he became a key member of the project working on the "Fat Man" A Bomb used on Nagasaki and also designed the equipment used to measure the blast wave for both A Bomb explosions. He flew as an observer on both Hiroshima and Nagasaki missions.
Luis Alvarez with flak jacket etc poses in front the B29 The Great Artiste which he flew on the 2nd A Bomb mission to Nagasaki as scientific observer.
In 1946 Alvarez was awarded the Collier Trophy by President Truman for his work on the GCA system. This was and still is a very prestigious award granted for outstanding contributions in the field of Aviation and Space Travel. The Ground Control Approach system did not enter widespread service with the RAF till after the war but was used with great success during the Berlin Airlift in 1948/49.
Written by David W Fell. Photos courtesy of Wikipedia.